21329418 has 32 divisors (see below), whose sum is σ = 48563712. Its totient is φ = 6182000.

The previous prime is 21329401. The next prime is 21329431. The reversal of 21329418 is 81492312.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5508 + ... + 8543.

It is an arithmetic number, because the mean of its divisors is an integer number (1517616).

Almost surely, 2^21329418 is an apocalyptic number.

21329418 is an abundant number, since it is smaller than the sum of its proper divisors (27234294).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21329418 is a wasteful number, since it uses less digits than its factorization.

21329418 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14090.

The product of its digits is 3456, while the sum is 30.

The square root of 21329418 is about 4618.3782868015. The cubic root of 21329418 is about 277.3275415740.

It can be divided in two parts, 213294 and 18, that added together give a palindrome (213312).

The spelling of 21329418 in words is "twenty-one million, three hundred twenty-nine thousand, four hundred eighteen".